The present invention relates to an airbag and an airbag system for protecting an occupant in a car crash and so on. In particular, the present invention relates to an airbag and an airbag system including a left airbag section and a right airbag section to be inflated on a left front and a right front of an occupant, respectively.
Japanese Patent Publication (Kokai) No. 04-292239 discloses an airbag for protecting an occupant in a car crash and so on, which includes a left airbag section and a right airbag section to be inflated on a left front and right front of an occupant, respectively, by a common inflator. In the airbag of the reference, distal ends of the left airbag section and the right airbag section are joined together with a tie panel.
The airbag is housed in a casing in a folded state and covered with a cover. When an inflator (gas generator) is activated to eject gas in a car crash, the airbag pushes the cover open to inflate toward the front of the occupant.
The inflator is arranged inside or outside a base end of the airbag. In an airbag system in which the inflator is arranged outside the base end of the airbag, gas ejected from the inflator is supplied into the airbag through a gas inlet at the base end of the airbag. When the inflator is arranged inside the base end of the airbag, the inflator may be entirely arranged in the airbag, or alternatively, a part of the inflator may be arranged in the airbag. The later example includes a structure in which a pair of slit-like openings is provided in the airbag, in which a rod-like inflator is inserted with both ends thereof projecting outside the airbag.
Patent Document 1: Japanese Patent Publication (Kokai) No. 04-292239
In the airbag including the left airbag section and the right airbag section disclosed in Japanese Patent Publication (Kokai) No. 04-292239, when the left airbag section and the right airbag section in an inflated state have large volumes, a high-capacity inflator is required to inflate the airbag at an early stage. Accordingly, it is an object of the present invention to provide an airbag and an airbag system in which a left airbag section and a right airbag section are inflated sufficiently at an early stage even when a capacity of an inflator is relatively low, thereby preventing interference with an A-pillar during the inflation.
In the airbag disclosed in Japanese Patent Publication (Kokai) No. 04-292239, the distal ends of the left airbag section and the right airbag section are joined together with a tie panel. Accordingly, when the airbag inflates, the tie panel receives a lateral center of an occupant body.
In the airbag disclosed in Japanese Patent Publication (Kokai) No. 04-292239, when the left airbag section and the right airbag section inflate, gas from the inflator flows more into one of the airbag sections than the other, so that the other airbag section might inflate later than the first airbag section.
In the airbag disclosed in the reference, the left airbag section and the right airbag section are joined together with a tie panel. Accordingly, even if one of the airbag sections inflates later than the other, the first inflating airbag section may pull the late inflating airbag section in the inflating direction with the tie panel to accelerate the inflation. However, since the tie panel connects the distal ends of the left airbag section and the right airbag section together, the first inflating airbag section can not sufficiently pull the late inflating airbag with the tie panel until it inflates to the distal end.
Accordingly, it is an object of the invention to provide an airbag and an airbag system in which an inflated left airbag section receives a left chest of an occupant and a right airbag section receives a right chest while a space of the inflated airbag faces a lateral center of the occupant chest.
It is another object of the invention to provide an airbag and an airbag system in which both of a left airbag section and a right airbag section are inflated smoothly and substantially evenly from an initial stage of inflation.
Further objects and advantages of the invention will be apparent from the following description of the invention.